Ink storage tube for ball-point pens

ABSTRACT

An ink reservoir which can allow a visual color to display a blue color without coloring the ink reservoir with a specific colorant.It is an ink reservoir for a ball point pen, in which fine particles for scattering light are contained in a resin composing the ink reservoir for a ball point pen and which makes it possible to transmit light.

This is a national phase application under 35 U.S.C. §371 ofInternational Application No. PCT/JP99/02775, filed May 26, 1999, andclaims the benefit under 35 U.S.C. §119 of Japanese Patent ApplicationNo. Hei 10-144757, filed May 26, 1998.

TECHNICAL FIELD

The present invention relates to an ink reservoir for a ball point penwhich can display a visual ink color and a ball point pen using thesame.

BACKGROUND ART

A ball point pen comprises a ball, a tip for holding the same and atube, which is connected with the tip and filled with an ink. The ballpoint pen feeds the ink to the ball through the tip and coats the ink(writes) on a paper surface. It is a matter of course that since the tipand the tube are fine, a holder which fixes the above tip and which hasa size suitable for writing with fingers is installed to constitute theball point pen.

This tube is an ink reservoir, and transparent or translucent ones areused in many cases so that an ink decrement due to use of the ink can beobserved.

An ink for a ball point pen, particularly an oil based ink for a ballpoint pen is compounded with a large amount of colorants, and when thecolorant is dyes, an appearance of the ink color displays apparently acolor almost close to black even when, for example, a black, red, blueor green ink is used.

When a pigment is used, a visual color of a blue or dark-blue ink of acool color, apart from an ink having a warm color displays a coloralmost close to black since the ink absorbs almost all of light.

Further, it is possible to obtain, for example, a red, blue or greentranslucent ink reservoir by coloring the ink reservoir. A translucentred, blue or green color can be observed in a part where the ink is notpresent, but a part where the ink is present displays a color almostclose to black. In addition thereto, such colored ink reservoir is notused for various ink colors.

Accordingly, there has been a problem in that when a conventional inkreservoir for a ball point pen in which coloring is not given to the inkreservoir itself is filled with an ink, a visual color thereof is a darkcolor in all cases and it is difficult to distinguish them from eachother.

DISCLOSURE OF THE INVENTION

An object of the present invention is to obtain an ink reservoir whichcan allow a visual color to display a blue color without coloring theink reservoir with a specific colorant.

1. An ink reservoir for a ball point pen, in which fine particles forscattering light are contained in a resin composing the ink reservoirfor a ball point pen and which makes it possible to transmit light.

2. The ink reservoir for a ball point pen as described in the above item1, wherein the fine particles dispersed in the resin composing the inkreservoir have an average particle diameter of 100 nm or less.

3. The ink reservoir for a ball point pen as described in the above item1 or 2, wherein the ink reservoir is made of polypropylene.

4. The ink reservoir for a ball point pen as described in the above item2, wherein the fine particle which is dispersed in the resin composingthe ink reservoir and which has an average particle diameter of 100 nmor less is titanium oxide.

5. A ball point pen using the ink reservoir for a ball point pen asdescribed in any one of the above items 1, 2, 3 and 4, wherein the inkfilled into the ink reservoir of the ball point pen is an oil based inkfor a ball point pen.

6. The ball point pen as described in the above item 5, wherein the oilbased ink for a ball point pen filled into the ink reservoir is a blueink.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a drawing showing the spectra of Samples 1 to 4.

FIG. 2 is one embodiment of a ball point pen of the present invention.

FIG. 3 is a partial sectional view of the ball point pen shown in FIG.2.

BEST MODE FOR CARRYING OUT THE INVENTION

The ball point pen of the present invention is exemplified in FIGS. 2and 3. As shown in FIG. 2, the ball point pen (10) comprises a ball(16), a tip (14) for holding the same and a body (12), which isconnected to the tip. An ink reservoir (22) is contained within the body(12) and comprises a resin (18) and particles (20) dispersed therein.The ink reservoir (22) holds an ink (24).

The fine particles for scattering light used in the present inventionhave preferably a size smaller than a wavelength of a visible ray andmay be, for example, preferably particles of a resin such as polystyrenebase resins, polystyrene-acryl base copolymers, acryl base resins, andinorganic powder such as fine powder silica, titanium oxide, zinc whiteand lead white.

The fine particles having an average particle diameter of 100 nm or lessare most preferred. Fine particle titanium oxide can be used as the fineparticles, and fine particle titanium oxide used in the presentinvention has suitably an average diameter of a single particle of 100nm or less determined by an electron microscope method, and commercialproducts thereof include MT-500B, 500SA, 500HD, 600B, 600SA, 100S and150W (all manufactured by TAYCA CORPORATION). They have a particlediameter of about 50 to 15 nm determined from a specific surface areabased on the assumption that they are spheres. In addition thereto,capable of being used are TTO-55 (A) and TTO-55 (B) (C) (D) (S) (N) (B)(D) (all manufactured by ISHIHARA SANGYO KAISHA LTD.), Super TitaniaF-1, 2, 3, 4, 5 and 6 and surface-treated products thereof (allmanufactured by SHOWA DENKO K.K.), and P-25 (manufactured by DegussaAG.).

A material for the ink reservoir used in the present invention may beany one as long as it has a resistance to a ink for a ball point penfilled without deforming or swelling and is so transparent that anamount of the ink filled can be observed. To be specific, capable ofbeing used are thermoplastic resins such as polypropylene, polyethylene,polyacrylonitrile base thermoplastic resins, polyethylene terephthalate,polyarylate and ethylene-vinyl alcohol copolymers. In particular,polypropylene is suited since it is inexpensive and has a transparencyand suitable strength and hardness.

It does not matter whether the ink for a ball point pen used in thepresent invention is a water based ink or an oil based ink, and apreferred example is an oil based ink for a ball point pen whichcontains a large amount of colorants and in which a visual color of theink is dark. More preferred is a blue ink which displays the same colorbetween the visible color of the ink reservoir for a ball point pen inwhich the particles for scattering light is contained according to thepresent invention and which can transmit light and the color of thedrawn lines.

It is considered that since the fine particles are contained anddispersed in the resin of the ink reservoir, a scattered light having awavelength in a short wavelength (400 to 500 nm) side of a visible rayis more strongly scattered and that since the ink filled has a darkcolor, an appearance of the ink reservoir displays a blue color.

The present invention shall more specifically be explained below withreference to examples, but the present invention shall by no means berestricted to these examples.

EXAMPLE 1

A polypropylene resin which was mixed with 0.1% by weight of fineparticle titanium oxide MT-500HD was extrusion-molded to obtain a thin,white translucent tube (A) having an outer diameter of 3 mm and an innerdiameter of 1.6 mm.

EXAMPLE 2

A propylene resin which was mixed with 0.2% by weight of fine particletitanium oxide MT-500SA was extrusion-molded to obtain a thin, whitetranslucent tube (A2) having an outer diameter of 3 mm and an innerdiameter of 1.6 mm.

COMPARATIVE EXAMPLE 1

Molding was carried out in the same manner as in Example 1, except thatfine particle titanium oxide was excluded to obtain a translucent tube(B) having an outer diameter of 3 mm and an inner diameter of 1.6 mm.

These tubes (A), (A2) and (B) were charged with a blue ink (C) and a redink (D).

The blue ink (C) was obtained by stirring the following blendingcomponents at 60° C. for 6 hours.

Blue ink (C): 2-Phenoxyethanol 35.0% by weight Benzyl alcohol 26.5% byweight Polyvinylpyrrolidone 0.5% by weight S. P. T. Blue-111 (dye, 30.0%by weight manufactured by HODOGAYA CHEMICAL CO., LTD.) Oleic acid 2.0%by weight Hilac 110H (ketone resin 6.0% by weight manufactured byHitachi Chemical Co., Ltd.)

Red ink (D): 2-Phenoxyethanol 41.5% by weight Benzyl alcohol 15.0% byweight Polyvinylpyrrolidone 0.5% by weight Spilon Yellow C-2GH (dye,5.0% by weight manufactured by HODOGAYA CHEMICAL CO., LTD.) Spilon RedC-GH (dye, 16.0% by weight manufactured by HODOGAYA CHEMICAL CO., LTD.)Oleic acid 2.0% by weight Hilac 110H (ketone resin 20.0% by weightmanufactured by Hitachi Chemical Co., Ltd.)

the example tube (A) (A2) and the comparative example tube (B) werecharged with the blue ink (C) and the red ink (D) respectively, andmounted with a ball point tip with a ball having a diameter of 0.7 mm toobtain ball point pens, whereby the following samples were prepared.

Sample 1: tube (A) of Example 1+blue ink (C)

Sample 2: tube (A2) of Example 2+red ink (D)

Sample 3: tube (B) of Comparative Example 1+blue ink (C)

Sample 4: tube (B) of Comparative Example 1+red ink (D)

Samples 1 to 4 had the colors thereof visually observed by 20 monitorsunder D65 standard light source F65D-A type (manufactured by Suga TestInstruments Co., Ltd.). The results thereof are shown in Table 1.

TABLE 1 Response/ Response/ blue black Uncertain Sample 1/example 20  00 Sample 2/example 18  0 2 Sample 3/comparison  0 20 0 Sample4/comparison  0 19 1

A 150φ integrating sphere (manufactured by Hitachi, Ltd.) for U3300 wasinstalled to a spectrophotometer U3300 (manufactured by Hitachi, Ltd.)to determine spectral reflectances of Samples 1 to 4 under the followingconditions:

Conditions:

Data mode: % T

Scanning speed: 600 nm/min

Wavelength range: 800.00 to 400.00 nm

Slit: 5.0 nm

Base line correction: aluminum oxide plate

Sampling interval: 2 nm

The spectra of Samples 1 to 4 are shown in FIG. 1. Peaks of bluereflected light are found in Samples 1 and 2 using the tubes (A and A2)prepared in the examples, and flat spectra are shown through themeasured wavelength range in Samples 3 and 4 using the tube prepared inthe comparative example.

INDUSTRIAL APPLICABILITY

An ink reservoir for a ball point pen in which fine particle titaniumoxide is blended into a resin composing the reservoir and through whichlight can be transmitted displays a blue color and beautiful appearanceeven when it was charged with an ink having a visual color which isalmost close to black. In addition thereto, since it transmits light, acontent of the ink can be discriminated. If a blue ink is used, a visualcolor of the ink reservoir is consistent with a hue of the drawn lines,and if the ball point pen ink reservoir and the holder thereof aretransparent, the user can visually observe at a glance from theappearance that it is a blue color ball point pen.

What is claimed is:
 1. An ink reservoir for a ball point pen comprisinga resin having fine particles with an average particle diameter of 100nm or less dispersed therein, the particles capable of scattering light.2. The ink reservoir for a ball point pen as described in claim 1,wherein the ink reservoir is made of polypropylene.
 3. A ball point penusing the ink reservoir for a ball point pen as described in claim 2,wherein the ink reservoir contains an oil based ink for a ball pointpen.
 4. The ball point pen as described in the claim 3, wherein the oilbased ink for a ball point pen filled into the ink reservoir is a blueink.
 5. The ink reservoir for a ball point pen as described in claim 1,wherein the fine particles are titanium oxide.
 6. A ball point pen usingthe ink reservoir for a ball point pen as described in claim 5, whereinthe ink reservoir contains an oil based ink for a ball point pen.
 7. Theball point pen as described in the claim 6, wherein the oil based inkfor a ball point pen filled into the ink reservoir is a blue ink.
 8. Aball point pen using the ink reservoir for a ball point pen as describedin claim 1, wherein the ink reservoir contains an oil based ink for aball point pen.
 9. The ball point pen as described in claim 8 whereinthe oil based ink for a ball point pen filled into the ink reservoir isblue ink.
 10. The ink reservoir of claim 1, wherein the particles arecapable of scattering visible light.
 11. The ink reservoir of claim 10,wherein the light has a wavelength of 400 to 500 nm.